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Centennial Building


Notice the black polished facing stone and beige travertine on the facing around the main entrance.

The black stone is from Digdeguash in southern New Brunswick. It is an igneous rock, which means the rock was once a molten magma. It is valued as it is uniform (the crystals are the same size, without blotchy lumps of other rocks having fallen in the magma, which can reduce the value of the stone). It also polishes nicely.

Did you know?.... It can take between 3 and 5 days to cut and polish an igneous rock! This includes those fancy granite counter tops you can buy for your home. That's partly why they are so expensive.

The Travertine is the light brown rock. Is it as solid and as uniform as the Digeduash igneous rock? Travertines usually form in areas like ancient waterfalls. The minerals in the water coat the rocks, algae and mosses around the waterfall, leaving a rock that is full of holes (where the organic material once was present).

EXERCISE:
One of these rocks is a form of limestone. Can you guess which one it is likely to be? A limestone is formed from the mineral calcite. If you happened to bring with you a sachet of vinegar (who doesn't walk around with one in their pocket?) then you will see that the limestone bubbles when the vinegar is placed on it. Were you correct at choosing in the correct rock as the limestone (the travertine or the Digdeguash igneous rock)?